Needle depth for microneedling

Dr. Wrassman, to clarify, are you expecting that this is a normal outcome?  I get bleeding and worry that I am going too hard and perhaps should consider less time or a shorter needle length? Quite frankly, it’s been tough to pin down an optimal needle length in the literature. I was considering restarting at 1mm with the dermapen assuming the 1.5mm rollers prevalent in literature only penetrate 1 – 1.25mm.

The stem cells lie under the epidermis which is 0.5mm below the scalp surface. The 1 or 1.5mm reaches this depth. Either should be fine. The key is to get wound healing that reaches the stem cells.